1)
What Midbar is discussed?
1.
Radak: It is Midbar Shur ("va'Yetz'u El Midbar Shur" - Shemos 15:22), which is also called Midbar Itam (in Bamidbar 34:33).
2)
What does "Ad Yam Suf" refer to?
1.
Rashi: It is south of Eretz Edom, and Edom is south of Eretz Kena'an.
2.
Radak: It was the third encampment after Keri'as Yam Suf - they camped at Marah, Eilim and Yam Suf (Bamidbar 33:8-10). Yiftach was concise, and mentioned only what was needed. There were other 1 encampments between Yam Suf and Kadesh.
1
There were 26 encampments in between (Bamidbar 33:10-36). I do not know why it was necessary to teach that they came to Yam Suf. (PF)
